Fan Problems - Audi A3 1.9TDI Sportback 2008

[doyley196]

HELP!!!!!

 

From one very frustrated Audi owner.

 

I have a Audi A3 TDI Sportback, 2008.

 

I have just had the A3 put on a diagnostic check to be told that the system is showing "healthy".

 

The big problem is that both radiator fans run a full speed as soon as you put the keys into a on position. Both fans do however switch off when you take keys out.

 

Also the air con will not operate - I have been told this is because one of the fans is controlling air con and it's getting a control from ecu not to operate. "Is this correct?"

 

So here's the general history of fault;

 

The particulate filter warning light came on, as per instructions in manual I took it down the motorway at 2000rpm in 4 gear until warning disappeared.

 

Next time this happened I was given a tip just to park up in a quiet street and idle the engine at 2000rpm - shouldn't have listened! That's when the radiator fault appeared.

 

Before anyone ask's - Here's what i've paid for so far. 2 new radiator fans because Audi mechanic said he'd checked the thermostat, ecu, wiring for loose joint etc.

 

The problem is still there even after changing both radiators at a expensive cost to myself.

 

Anyone had this problem or could someone point me in the right direction.

 

Thanks. 

[Tech]

Hi,

 

There could be a number of things causing this problem.  If the PWM signal to the radiator fan ECU has a wiring fault (e.g. short to live) this could cause the problem.  Also the engine ECU could be telling the fans purposely to run at full speed, if it believes something is too warm, due to a faulty temperature monitoring for example.

 

However, seeing as you have also mentioned your AC is not working, I would suggest that your 'Audi mechanic' checks the measured value block for the air conditioning refrigerant pressure sensor.  If this is reading too high, due to a faulty sensor or short circuit on the wiring, it will cause the fans to run at full speed and the air conditioning not to work (the compressor will be cut off as it already thinks the pressure is too high).  

 

Did you get this looked at by an Audi dealership or somebody claiming to be an 'Audi mechanic'?

 

Tech

[doyley196]

Many Thanks to everyone for advice. The problem was a faulty pressure sensor on air conditioning side. Thank You very much.

[Tech]

No problem, glad to be of help!